ML17263A225

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LER 93-001-00:on 930312,both Source Range Detectors Found Inoperable During Energization.Caused by Center Electrode Degradation Due to Gamma Corrosion.Failed Detectors Replaced W/Qualified spares.W/930412 Ltr
ML17263A225
Person / Time
Site: Ginna Constellation icon.png
Issue date: 04/12/1993
From: BACKUS W H, MECREDY R C
ROCHESTER GAS & ELECTRIC CORP.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-001, LER-93-1, NUDOCS 9304160043
Download: ML17263A225 (26)


Text

ACCEI.EEDDOCUMENTDISOBVTIONSYSTEMREGULAORYINFORMATION DISTRIBUT 8SYSTEM(RIDS)ACCESSION NBR:9304160043 DOC.DATE:

93/04/12NOTARIZED:

NOFACIL:50-244 RobertEmmetGinnaNuclearPlant,Unit1,Rochester GAUTH.NAMEAUTHORAFFILIATION BACKUSgWHERochester Gas&ElectricCorp.MECREDY,R.C.

Rochester Gas&ElectricCorp.RECIP.NAME RECIPIENT AFFILIATION DOCKET05000244

SUBJECT:

LER93-001-00:on 930312,both sourcerangedetectors foundinoperable duringenergization.Caused bycenterelectrode degradation duetogammacorrosion.

Faileddetectors replacedw/qualified spares.W/930412 ltr.DISTRIBUTION CODE:IE22TCOPIESRECEIVED:LTR ENCLSIZE:TITLE:50.73/50.9 LicenseeEventReport(LER),ncidentRpt,etc.NOTES:License Expdateinaccordance with10CFR2,2.109(9/19/72).

05000244RECIPIENT IDCODE/NAME PD1-3LAJOHNSONiA INTERNAL:

ACNWAEOD/DSP/TPAB NRR/DE/EELB NRR/DORS/OEAB NRR/DRCH/HICB NRR/DRIL/RPEB RR7'DSSA/

PLBGFILE02RGNE01EXTERNAL'G&GBRYCEgJ~HNRCPDRNSICPOOREiW.COPIESLTTRENCL1111221111111111111111221111RECIPIENT IDCODE/NAME PD1-3PDAEOD/DOAAEOD/ROAB/DSP NRR/DE/EMEB NRR/DRCH/HHFB NRR/DRCH/HOLB NRR/DRSS/PRPB NRR/DSSA/SRXB RES/DSIR/EIB LSTLOBBYWARDNSICMURPHY,G.ANUDOCSFULLTXTCOPIESLTTRENCL111122111111221111111111f'2374pQgc5NOTETOALL"RIDS"RECIPIENTS:

$0-tPLEASEHELPUSTOREDUCEWASTE!CONTACTTHEDOCUMENTCONTROLDESK,ROOMPI-37(EXT.504-2065)

TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDON'TNEED!FULLTEXTCONVERSION REQUIREDTOTALNUMBEROFCOPIESREQUIRED:

LTTR30ENCL30

JJrROCHESTER GASANDELECTRICCORPORATION

,r'~".'rOarrtEt~jStJlf489EASTAVENUE,ROCHESTER N.K14649-0001 ROBERTC.h1ECREDYVicePresident CrnnJNucteJrProduction TELEPHONE AREACODE7i65462700April12,1993U.S.NuclearRegulatory Commission DocumentControlDeskNashington, DC20555

Subject:

LER93-001,LossofSourceRangeDetectorIndication DuringEnergization, DuetoFaultyDetectors, CausesaCondition Prohibited byPlantTechnical Specifica-tions.R.E.GinnaNuclearPowerPlantDocketNo.50-244Inaccordance with10CFR50.73,LicenseeEventReportSystem,item(a)(2)(i)(B),

whichrequiresareportof,"anyoperation prohibited bytheplant'sTechnical Specifications",

theattachedLicenseeEventReportLER93-001isherebysubmitted.

Thiseventhasinnowayaffectedthepublic'shealthandsafety.Verytrulyyours,XCJRobertC.MeredyU.S.NuclearRegulatory Commission RegionI475Allendale RoadKingofPrussia,PA19406GinnaUSNRCSeniorResidentInspector IGG030'9304160043 930412PDRADOCK05000244S'PDR~'I>]gdIf

NACFORM300(Se)9)US.NUCLEARREGULATORY COMMISSIAPPAOVEDOMBNO.3)500(OCEXPIRF5:C/30/92ESTIMATED BURDENPERRFSPONSETOCOMPLYWTHTHISINFORMATIOAI COLLKCTION AEOUESTI50.0HAS.FORWARDCOMMENTSREGARDING BUADENESTIMATETOTHERECORDSANDRFPORTSMANAGEMENT BRANCH(F030).U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON.

DC20555,ANDTOTHEPAPEAWORK ABDUCTION PROiECT(31500'IOe).

OFFICEOFMANAGEMENT ANDBUDGET.WASHINGTON, DC20503.LICENSEEEVENTREPORT(LER)DOCKETNUMBER(2)PA'FACILITYNAME(1)R.E.GinnaNuclearPowerPlanto5ooo244ioFllTITLE(e)LossofSourceRangeDetectorIndication DuringEnergization, DuetoFaultyDetectors CausesaCondition Prohibited vTechnical Snecifica io~yCC~'VENTDATE(SlLEANUMBER(0)REPORTDATE(7OTHERFACILITIES INVOLVED(0)MONTHOAYYEARYEARIg@SEQUENTIAL NUMSERREVISIONMONTHOAYYEARFACILITYNAMESDOCKETNUMBFRISI 050000312939300100041293~~05000OPERATING MODE(0)NPOWERLEVELppp20.I02(0) 20.e00(~)IIIIII20A05(el(1)(9)20.005(e) ll1(ill)20A054)ll)Grl20.405(~Ill)4)20.e05(~)BOM(c)(I)50.30(cl(2) 50.73(eI(2IIII50.73(e)(2)IIII50.734)(2)(III)

LICENSFECONTACTFOATHISLER(12)50,73leI(2)IIr)50.73(el(2) 4l50.73(e)(2) lrQ)50.73(e)(2)(rljj)

(A)50.73(el(2)(r(QI(

~)50.73(e)(2)(el0THEREDUIREMENTS OF10CFR():(Checkonrormoreofthefo//owindi (11)THISREPORTISSUBMITTED PURSUANTT73.71(III 73.71(c)OTHERISptcifycnAtjttrect Orrowrot/lnyrrt,/j/RCForm300AINAMEWes1eyH.BackusTechnical Assistant totheOoerations ManaerTELEPHONE NUMBERAREACODE315524-4446COMPLETEONELINEFOREACHCOMPONENT FAILUREOKSCRIBED INTHISREPORTll3)CCAUSESYSTEMCOMPONENT MANUFAC.TURERREPORTABLE TONPADSj~jPN~QQcAUsESYSTEMCOMPONENT MANUFAC.TURKREPOATABLE (cTONPRDSQtMY.'NUwY,IGDTW12pSUPPLEMKNTAL REPORl'XPECTED (IC)EXPECTEDSUBMISSION DATK(15)kklk)MI.QjtKiPyX~(MONTHOAYYEARYESIIIyrt,complrttEXPECTEDSt/der/SSION DATEINOABSTRACTILlmlttoIrddtpecrt,I,r.,rppror/mrtrfy Iifttenrindle.eptcr typrwrittrn

/inrdI10)OnMarch12,1993,at1425EST,viththereactorsubcritical duringaplannedshutdown, bothsourcerangedetectors verefoundinoperable withthereactortripbreakersclosed.TheControlRoomoperators immediately enteredandperformed theapplicable actionsofequipment restoration procedure ER-NZSe1(SRMalfunction).

Thereactortripbreakersvereopenedvithinfive(5)minutesoftheevent.Themostlikelycauseofthesourcerangedetectorfailureswascenterelectrode degradation duetogammacorrosion ofthebaretungstencenter~e"trode(centerwire).(ThiseventisNUREG--1022(B)causecode).Corrective actionwastoreplacethefaileddetectors vithqualified spares.Corrective actiontopreventrecurrence isoutlinedinsectionV(B).NRCForm300(509)

NRCFORM3SSA(649)US,NUCLEARREGULATORY COMMISSION LlCENSEEEVENTREPORT(LER)TEXTCONTINUATlON APPROVEDOMBNO,3150010S EXPIRES:4/30/92ESTIMATED BURDENPERRESPONSETOCOMPLYIYTHTHISINFORMATION COLLECTION REOUEST:500HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENT BRANCH(F430),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555,ANDTOSHEPAPERWORK REDUCTION PROJECT(31500)04),

OFFICEOFMANAGEMENT ANDBUDGET,WASHINGTON.

DC20503.FACILITYNAME(1)DOCKETNUMBER(2)YEARLERNUMBER(8)??oSEOUCNTIAL

>5~REVrdr0N?.'/1/NUMddASP/r)NUMEAPAGE(3)R.E.GlnnaNuclearPowerPlantTEXT///mored/rdee/d//r/rer/ude/(r)roe/ir//IC Form3//S42/(12) osooo24493-0010002oFl1PRE-PMNTCONDITONSAplantshutdownwasinprogressperoperating procedure 0-2.1(NormalShutdowntoHotShutdown) fortheannualrefueling andmaintenance outage.Theturbinegenerator hadgust.beentakenoffthelineandControlRoomoperators

'wereintheprocessofshuttingthereactordownandinserting allcontrolandshutdownrods.DESCRIPTION OFEVENTDATESANDAPPROXIMATE TIMESOFMAZOROCCURRENCES oMarch12,1993,1425EST:EventdateandtimeoMarch12,1993,1425,EST:Eventdiscovery dateandtimeoMarch12,1993,1430EST:ControlRoomoperators completeinserting allcontrolandshutdownrodsandopenthereactortripbreakers.

oMarch12,1993,1435EST:Plantstabilized athotshutdown.

oMarch12,1993,1501EST:SourceRangeNISN-31andNISN-32declaredinoperable.

oMarch12,1993,1730EST:SourceRangeNISN-32declaredoperableusingtheinstalled sparesourcerangedetector.

oMarch16,1993,1747EST:SourceRangeNISN-31declaredoperable.

oMarch17,1993,2040EST:SourceRangeNISN-32declaredoperable, usingitsnormalsourcerangedetector.

NRCPenn388A(589)

NRCFORM366A(689)U.S.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVEDOM6NO.31500106EXPIRES:6/30/92ESTIMATED BURDENPERRESPONSETOCOMPLYWTHTHISLNFORMATION COLLECTION REGUEST:50.0HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATEToTHERECORDSANDREPORTSMANAGEMENT SRANCH(PJ)30).U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555,ANDTO1HEPAPERWORK REDUCTION PROJECT(3)500106),

OFFICEOFMANAGEMENT ANOBUDGET,WASHINGTON.

DC20503.FACILITYNAME(I)DOCKETNUMBER(2)LERNUMBER(6)YEARO~>:SSOUSNTIAI v~4'EVISION NVM66R'&-NUMFSAI'AGEI3)R.E.GinnaNuclearPaverPlantTEXTlllmototptcoitttquia/,

uttAt//oont/P/RC%%dmt36SA't/(IT) 0s0002~~93p010003DF11B.EVENT-OnMarch12,1993atapproximately 1425ESTwiththereactorsubcritical duringaplannedshutdown, sourcerange(SR)NuclearInstrumentation System(NIS)ChannelN-31andChannelN-32automatically energized atthenormalsetpointof</=5E-11ampsonthetwointermediate range(IR)NISchannels.

TheControl.Roomoperators werecloselymonitoring thedecayoftheintermediate rangecurrents, andwereanticipating the'resetlevelforthe.sourceranges.Atthetimeofautomatic energization ofthesourcerangedetec-tors,therewasnocountrateindication onChannelN-31orChannelN-32.Seeingnoindication ofcountrate,theControlRoomoperators, inaccordance withplantprocedures andtrainingguidance, immediately attempted tomanually.energizethesourcerangedetectors usingtheP-6defeatpushbuttons.

Thesourcerangedetectors stilldidnotindicatecounts.TheControlRoomoperators continued toexpeditiously insertcontrolandshutdownrodsper0-2.1andatapproximately 1430ESTthereactortripbreakerswereopened.Theplant,was subsequently stabilized inhotshutdownatapproximately 1435EST.NRCForm366A(649)

NRCFORM366A(64)9)US.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVEDOMBNO.3ISOOI04 EXPIRESI4/30/92ESTIMATED BURDENPERRESPONSETOCOMPLYWTHTHISINFORMATION COLLECTION REOUEST:50.0HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENT BRANCH(P4)30),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555,ANDTOTHEPAPERWORK REDUCTION PROJECT(31504)104).

OFFICEOFMANAGEMFNT ANDBUDGET,WASHINGTON,OC 20503.FACILITYNAME(1)DOCKETNUMBER(2)YEARLERNUMBER(6)SEOUENZIAL,Oi)i NUMB%4AEVISIONNUMO64PAGE(3)R.E.GlnnaNuclearPowerPlantTEXT///mom4/>>ooJF~os,uood/d/ooo/NRCFomI35549/()7)osooo24493-00100040F~Subsequently theControlRoomoperators notifiedhighersupervision andtheInstrument

&Control(I&C)Department oftheeventandatapproximately 1501ESTdeclaredsourcerangeNISN-31andN-32inoperable.

ThePlantOperation ReviewCommittee (PORC)wasconvenedtoreviewtheactionstaken,conformance toTechnical Specifications, eventclassification andreportability.

PORCdirectedthataccesstotheContainment Building(CNMT)beprohibited untilonesourcerangechannelwasrestoredtooperablestatus.InadditionPORCconfirmed thatactionsweretakentoensureplantcooldownwouldnotoccur,andthatdilutionofboronconcentration wouldnotoccur.TheControlRoomoperators enteredandperformed theapplicable actionsofequipment, restoration procedure ER-NIS.1(SRMalfunction) including continued borationtogreaterthan54shutdownmargin.andsamplingtheReactorCoolantSystem(RCS).forboronconcentration onaperiodicbasisduringtheboration.

C.INOPERABLE STRUCTUEUKSF COMPONENTS, ORSYSTEMSTHATCONTRIBUTED TOTHE15TENT:D.None.OTE&RSYSTEMSORSECONDARY FUNCTIONS AFFECTED:

None.EMETHODOPDISCOVERY Theeventwasimmediately apparentduetoindications intheControlRoom.NRCFoIm366A(64)9)

NRCFORM366A(689)US.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION

~APPROVEDOMBNO,315001065XPIRES:6/30/92ESTIMATED BURDENPERRESPONSETOCOMPLYWTHTHISINFOAMATION COLLECTION REQUEST:500HRS.FORWARDCOMMENTSREGARDING BUAOENESTIMATETOTHERECORDSANDREPORTSMANAGEMENT BRANCH(P430),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON.

DC20555,ANDTOTHEPAPERWORK REDUCTION PROJECT(31500106).

OFFICEOFMANAGEMENT ANDBUDGET.WASHINGTON, OC20503.FACILITYNAMEn)DOCKETNUMBER(2)LERNUMBER(6)YEARLPNLSEQUENTIAI.

+WC:REVISIONI+I:NUMEER4.'UMERPAGED))R.E.GinnaNuclearPoT6erPlantJEXT///6NKEEpecris>>6U9od.

u>>>>M/6'one/N/IC Form35569)nl)osooo24493-010005OFPOPERATORACTIONTheControlRoomoperators, afterrecognizing thattherewerenoindicated countratesoneitherofthesourcerangedetectors, immediately attempted tomanuallyenergizethe-sourcerangedetectors usingtheP-6defeatpushbuttons.

Theoperators enteredER-NIS.1andperformed theapplicable actions,including pullingthefusesforInstrument Power,inanotherattempttoreinstate, thesource'anges.

Subsequently, theControlRoomoperators notifiedhighersupervision

'andtheI&CDepartment anddeclaredsourcerangeNISN-31andN-32inoperable.

G.SAFETYSYSTEMRESPONSES None.III.CAUSEOFOSTENTA.IMMEDIATE CAUSEThecauseofthefailureofsourcerangedetectors N-31andN-32toindicatecountswasdetectorfailureduetocenterelectrode degradation.

Specificmeasurements indicatethatthecenterelectrode toshieldhadbecomeshortcircuited onsourcerangedetectorN-31,most,likelyduetotheelectrode breakingatthebottomofthedetector.

SourcerangedetectorN-32wasfoundtobeopencircuited, possiblyduetotheelectrode breakingatthetopofthedetector.

NACForm366A(689)

NRCFORM366AISS9)US.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVEDOMSNO.31600104EXPIRES:E/30/92ESTIMATED BURDENPERRESPONSETOCOMPLYWTHTHISINFORMATION COLLECTION REOUESTI603)HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENT BRANCHIF@30),U,S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20655,ANDTO1HEPAPERWORK REDUCTION PROJECT131600)04),

OFFICEOFMANAGEMENT ANDBUDGET,WASHINGTON, DC20603.FACILITYNAME11)DOCKETNUMBER12)YEARLERNUMBERIS)X6%SEOUENTIAI.

NUMBERREVISIONNUMSERPAGE13)R.E.GonnaNuclearPowerPlantTEXTillmoroEPocolrrorlrr/rod, IrwoddldorM/ll/IC Forrrr366AS/)17) osooo24493-0010006OFBROOTCAUSE:Afterconsulting withWestinghouse ElectricCorporation (themanufacturer andvendorforthesedetectors),

itwasconcluded thattheunderlying causeofthecenterelectrode degradation ofsourcerangedetectors N-31andN-32ismostlikelyduetogammacorrosion ofthebaretungstencenterelectrode (centerwire).Thiseffectoccurswheneverthesourcerangedetectorisenergized.

ANALYSISOpEVENTTheeventisreportable inaccordance with10CFR50.73,LicenseeEventReportSystem,item(a)(2)(i)(B),

whichrequiresareportof,"anyoperation prohibited bytheplant'sTechnical Specification",

inthatthefailureofsourcerangedetectors N-31andN-32toindicatecountsat</=1E-10ampsonthetwointermediate rangeNISchannelswasanoperation prohibited bytheplantTechnical Specifications asfollows:oSpecification 3.5.1.1states,"TheProtection SystemInstrumentation shownonTable3.5-1shallbeoperablewhenevertheconditions specified inColumn6areexceeded".

Forthesourcerangeinstruments, column6referstoNote2,whichstates,"Channels shouldbeoperableatallmodesbelowthebypasscondition withthereactortripsystembreakersintheclosedpositionandcontrolroddrivesystemcapableofrodwithdrawal".

Contrarytotheabove,sourcerangechannelsN-31andN-32wereinoperable belowthebypasscondition of</=1E-10onbothIRNISchannelswiththereactortripbreakersclosedandthecontrolroddrivesystemcapableofrodwithdrawal.

Thiscondition existedforapproximately five(5)minutesuntilthereactortripbreakerswereopened.WhileanActionStatement existsforonesourcedetectorinoperable, thereisnostatedactionrequirement fortwo,detectors inoperable withtheReactorTripbreakersclosed.Therefore, acondition prohibited bytheplant'sTechnical Specifications existed.NRCForm366A)689)

NRCFORM366A(669)U.S.NUCLEARREGULATORY COMMISSION 2~LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVEDOMBNO.3(600104EXPIRES:A/30/92ESTIMATED BURDENPERRESPONSETOCOMPLYWTHTHISINFORMATION COLLECTION REOUESTI500HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATEToTHERECORDSANDREPORTSMANAGEMENT BRANCH(P430),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555,ANDTo1HEPAPERWORK REDUCTION PROJECT(3150010I),

OFFICEOFMANAGEMENT ANDBUDGET,WASHINGTON, DC20503.FACILITYNAME(11DOCKETNUMBER(2)LERNUMBER(6)PAGE(3)R.E.GinnaNuclearPowerPlantTEXT/I/momH>>ce/t>>I)r/irer/

Ir>>pr/r//I/orN/HRC Form366AB/(17)YEAR~rA0s00024493SEOUENTIAL NUMSER001<~~REVISION..IH:NUMER00070F11Oncethetripbreakersareopen,theminimumoperablechannelsrequiredreducestoone(1)insteadoftwo(2)andtheactionstatement statesinpartasfollows:Withthenumberofoperablechannelsonelessthantheminimumoperablechannelsrequirement, suspendalloperations involving positivereactivity changes.Anassessment wasperformed considering boththesafetyconsequences andimplications ofthiseventwiththefollowing resultsandconclusions:

Thesafetysignificance ofthefailureofbothsourcerangechannelsisthelossofdetection ofsubcritical neutronfluxinthecoreandthefunctionthosechannelsprovideforbothautomatic actuation ofthereactorprotection systemandtheprompting ofoperatoractiontoprotectshutdownmargin.However,thissignificance isminimized inthisinstanceforthefollowing reasons:0Thefailureoccurredcompletely withinthesequenceofshuttingdownthe-reactor inaccordance withplantprocedure 0-2.1inthattheoperators werecloselymonitoring thedecayoftheintermediate rangecurrentsandwereanticipating theresetlevelforthesourceranges.lnaccordance with0-2.1theoperators wereex-peditiously inserting thecontrolandshutdownrodstofivestepspriortomanuallyopeningthereactortripbreakers.

Thissequence, simultaneous withinjecting boricacidtoachievetherequiredRCScoldshutdownboronconcentration insuredthatshutdownmarginwasmaintained greaterthantherequirements ofTechnical Specifications, andthatshutdownmargindidnotdecreaseduringthisevent.NRCForm366A(BJ)9)

J NRCFORM355A(689)U.S.NUCLEARREGULATORY COMMISSION LICENSEEEYENTREPORTILER)TEXTCONTINUATION APPROVEDOMBNO.31600104EXPIRES:4/30JS2ESTIMATED BURDENPERRESPONSETOCOMPLYWTHTHISINFORMATION COLLECTION REQUESTI50.0HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENT BRANCH(P430),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555,ANDTO1HEPAPERWORK REDUCTION PROJECT(31504104).

OFFICEOFMANAGEMENT ANDBUDGET,WASHINGTON, OC20503.FACILITYNAME(1)DOCKETNUMBER(21LERNUMBER(5)YEAR(PSEQUENTIALS)I(REVISION M3NUMSEA'P..:NUMBERPAGE(3)R.E.GinnaNuclearPowerPlantTEXTFITmo>>~JJ>>ookod, u>>aktJNealHRCAnn35543)(IT)osooo24493-0010008OioAfterimmediately recognizing thatthesourcerangechannelsdidnotindicatecountsattheintermediate rangeresetpoint,theoperators tookappropriate actionsinattempting-toreinstate

-sourcerangedetectors.

Theycontinued toexpeditiously insertcontrolandshutdownrods,andwithinfiveminutes,openedthereactortripbreakers.

Theoperatorcontinued borationtothecoldshutdown, xenonfreeconcentration requiredbyprocedure forRCScooldownbelow500degrees.Therewasnodecreaseinshutdownmargin,fromthetime'offailureofbothsourcerangechannelsuntilthetimethesparesourcerangedetectorwasusedtodeclareChannelN-32operable.

Alloperations involving positivereactivity changesweresuspenders untilafterthesparesourcerangedetectorwasdeclaredoperable.

Basedontheabove,itcanbeconcluded thatthepublic'shealthandsafetywasassuredatalltimes.VCORRECTIVE ACTIONAACTIONTAKENTORETURNAFFECTEDSYST1963TOPRE-EVENT NORMALSTATUS:0,Thedetectorinstalled insourcerangechannelN-32wasdisconnected andthepreviously installed sparesourcerangedetectorwasconnected tosourcerangechannelN-32.NISN-32highvoltagesettingandthepulseheightdiscriminator (PHD)biassettingweread)ustedtoconformtothedataforthesparedetector.

Atapproxi-mately1730ESTonMarch12,1993,sourcerangeChannelN-32wasdeclaredoperable.

NRCForm365A(SSS)

NRCFORM366A(669)U.S.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVED0MBNO.31500)04EXPIRES:6/30)92ESTIMATED BURDENPERRESPONSETOCOMPLYWTHTHISINFORMATION COLLECTION REQUEST:500HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENT BRANCH(P630),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, OC20555,ANDTO1'HEPAPERWORK REDUCTION PROJECT(31500106),

OFFICEOFMANAGEMENT ANDBUDGET,WASHINGTON, DC20503,FACILITYNAME(I)DOCKETNUMBER(2)LERNUMBER(6)YEARS~ySEQVSNTIAL

~2NUMSSIIREVISIONNUMSAPAGE(3)R.E.GonnaNuclearPowerPlantTEXTNmonJIMcels~,VJP~HRCForm35663)(IT)ppppp24430010009oF11Thedetectorinstalled insourcerangechannelN-31wasreplacedwithadetectorwithdrawn fromstock.Subsequently, forsourcerangechannelN-31thehighvoltagepowersupplywasreplaced.

Thedetectoranodevoltagecurve(alsoreferredtoastheplateaucurve).wasobtained, andthePHDbiassettingwasadjusted.

Atapproximately 1747ESTonMarch16,1993,sourcerangeChannelN-31wasdeclaredoperable.

oThedetectorinstalled insourcerangechannelN-32wasreplacedwithadetectorwithdrawn fromstock.Forthisnewlyinstalled

detector, theplateaucurvewasobtainedandthePHDbiassettingwasadjusted.

Theinstalled sparesourcerangedetectorwasthendisconnected fromsourcerangechannelN-32andthisnewlyinstalled sourcerangedetectorwasconnected tosourcerangechannelN-32..Thechanneloperability testwascompleted, andatapproximately 2040ESTonMarch17,1993sourcerangeChannelN-32wasdeclaredoperable, usingitsnormalsourcerangedetector.

BACTIONTAKENORPLANN19)TONUGENTREC&tRENCE:

Tominimizefuturesourcerangedetectorfailures, thefollowing actionsarebeingplanned:0Aperiodicreplacement intervalforBF~filledsourcerangedetectors willbeestablished, basedupontimeinserviceornumberofener-gizations ofthedetectors.

NRCForm366A(689)

NRCFORM366A(689)FACILITYNAME(1)UE.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORTtLER)TEXTCONTINUATION DOCKETNUMBER(2)APPROVEDOM8NO.31600104EXPIRES:4/30/92ESTIMATED BURDENPERRESPONSETOCOMPLYWTHTHISINFORMATION COLLECTION REQUEST:50/)HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENT BRANCH(P830),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555,ANDTOTHEPAPERWORK REDUCTION PROJECT(31500104).

OFFICEOFMANAGEMENT ANDBUDGET,WASHINGTON, DC20503.PAGE(3)LERNUMBER(8)YEARP444SEQUENTIAL

.AyNUMSERREVISIONNUMSSRR.E.GonnaNuclearPowerPlaneTEXT///mareS>>ceJIre/Ir/red, Ireeedd/dar>>/N/IC

%%drm38642/((7)psppp244930010010OFoAnewWestinghouse designfortheseBF3filledsourcerangedetectors incorporates lowvoltagesourcerangedetectors withgold-plated tungstencenterwireconductor material.

Detectors ofthisnewdesignwillbeprocured.

Whendetectors ofthisnewdesignareinstalled, aspartofaplanneddetectorupgradeschedule, asreplace-mentsforexistingdetectors, theperiodicreplacement intervalwillbere-evaluated.

0Existingcalibration procedures willberevised,"ornewprocedures developed, toincludestepstoperformtimedomainreflectometry (TDR)measure-mentsonN-31,N-32andsparedetector, priortoscheduled refueling outages.(TDRmeasurements candetermine ifthedetectorcenterelectrode wireisbroken,shortedoutorifithashighorlowresistance)

.0Atrendingprogramtodetectpotential degradation ofsourcerangedetectors willbeestablished, forthefollowing data:1)Detectorplateaucurvedatawillbetrended.AstheBF3gasinthedetectordissociates overtime,thehighvoltagewillbeadjustedhighereachtimeuntilitcannolongerbesetontheplateau.2)PHDbiascurveswillbetrended.RMATONAPAXLEDCOMPONENTS:

Thefaultydetectors wereBF3filled,sourcerangedetectorproportional

counters, PartNo.WL-24182manufactured byWestinghouse ElectricCorporation.

NRCForm388A(889)

NRCFORM366A(SJ)9)tUS.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVEOOMBNO,31500104EXPIRES:EI30(92ESTIMATED BURDENPERRESPONSETOCOMPLYWTHTHISINFORMATION COLLECTION REQUEST:500HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENT BRANCH(F430).U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON.

OC20555,ANDTO1HEPAPERWORK REDUCTION PROJECT(31500104).

OFFICEOFMANAGEMENT ANDBUDGET,WASHINGTON, DC20503.FACILITYNAME(1IDOCKETNUMBER(2)YEARLERNUMBER(SISEQUENTIAL NVMSERREVISIONNVMSERI'AGE(3)R.E.GinnaNuclearPowerPlantRJOOOOPooo (ssoSs(INL goooddlooIMI HRC%%dmI36643)(17)osooo244930010011OFB.PREVXOUSLERsONSIMILARKGFNTS.AsimilarLEReventhistorical searchwasconducted withthefollowing results:LER90-003(HigherThanNormalCountRateonSourceRangeNIS,DuetoaFaultyDetector, CausesaReactorTripDuringSourceRangeRe-energization) wasasimilareventwiththesamerootcause.Thecorrective actiontopreventrecur-rence,oftheeventdescribed inLER90-003,wastoinitiateaevaluation whichwillultimately resultinprocurement andinstallation ofdetectors, ofanewWestinghouse design.Itshouldbenotedthateveniftheevaluation hadbeencompleted, anddetectors ofanewdesignhadbeenprocuredandwereinstock,thesedetectors wouldnothavebeeninstalled priortothe1993outage.CSPECIALCOMMENTSNone.NRCFoIm366A(SJ)9)